The present invention relates in general to electromechanical actuators, and, in particular to transmission range selection system including an actuator for controlling the gear position of an automotive transmission through a driver interface and an electronic control module.
Conventional automobile transmissions are controlled through a gear shift assembly connected to the transmission through a mechanical linkage. The gear shift is normally prominently positioned adjacent the driver""s seat for easy access. In a vehicle having either an automatic or a manual transmission, to change the transmission gear position the operator moves the gear shift to a position corresponding to the intended gear position, e.g., park, neutral, drive, reverse, etc.
Unfortunately, known mechanical transmission gear shift assemblies occupy a significant amount of passenger compartment space. Compartment space has always been a valuable commodity in automobile design. With the introduction of new features and technologies to automobiles, compartment space is becoming increasingly valuable.
For example, many automobiles today include cellular phones, computerized global positioning systems, increased storage area, etc. Future automobile designs will likely include full computer displays and associated equipment. All of the equipment related to new technologies introduced into automobile designs must be positioned in the already limited space adjacent the driver""s seat. It is recognized, therefore, that reducing the size and space requirements of conventional transmission shift assemblies would be highly beneficial in terms of providing additional space adjacent the driver for the introduction of new equipment.
There is, therefore, a need in the art for a compact, cost-effective, and reliable transmission range selector system that may be conveniently operated and efficiently assembled to an automobile.
The present invention is organized about the concept providing a compact, cost-effective, and reliable transmission range selector system that may be conveniently operated and efficiently assembled to an automobile. A transmission range selector system consistent with the invention may include a driver interface module, an electronic control module, and an actuator coupleable to an automotive transmission. In one embodiment, the driver interface module may be positioned in a plurality of desired transmission gear positions. The desired gear position set at the driver interface module is redundantly sensed by the combination of a rotational position Hall effect sensor and a plurality of discrete position Hall effect sensors. The rotational position Hall effect sensor may have a linearly varying output representative of the desired gear position. The Hall effect sensors provide an output to the electronic control module for energizing the actuator to change the transmission gear position to the desired transmission gear set at the driver interface module. The actuator may include multiple motors to provide redundancy and a sensor gear for providing transmission gear position feedback to the electronic control module.
In particular, a system consistent with the present invention may include: a driver interface module including a portion moveable to a plurality of desired gear positions; at least one sensor for providing an associated output signal in response to movement of the portion to at least one of the desired gear positions; and an actuator for positioning the transmission in at least one of the desired gear positions in response to the output signal. The driver interface module may include an axle that rotates with movement of the movable portion and a magnet disposed on an end of the axle, and the sensor may be a rotational position Hall effect sensor disposed adjacent the magnet. The magnet may be disposed eccentrically on the end of the axle to provide a linearly varying output signal having distinct voltage levels associated with each of the desired gear positions. The actuator may be configured to move the transmission to a respective one of the desired gear positions associated with each of the distinct voltage levels.
The system may also include a plurality of discrete position Hall effect sensors, and the movable portion of the interface module may be a shaft having a magnet disposed thereon. The magnet may be disposed adjacent a respective one of the discrete position Hall effect sensors when shaft is in each of the plurality of positions. Each of the discrete position Hall effect sensors may provide a distinct output signal associated with a respective one of the desired gear positions. The actuator may be configured to move the transmission to a respective one of the desired gear positions in response to each of the distinct output signals.
The actuator may include at least one electric motor for driving a gear train in response to the output signal. The gear train may include an output gear having output shaft for moving the transmission to the desired gear positions and a sensor gear, the sensor gear having a magnet disposed eccentrically on an end thereof. At least one Hall effect sensor may be disposed adjacent the magnet for providing an actuator output signal representative of the rotational position of the output shaft. The output signal may vary substantially linearly with rotation of the sensor gear. First and second electric motors and first and second Hall effect sensors may be used to provide redundancy.